Don't worry about a bit of bleeding- the gynae will be more than used to it. When I did gynae, I used to have to internally examine women who were having miscarriages and obviously while in labour- neither of which are that clean and tidy!
I would still go. Chances are even if you made another appointment you'd find that your cycle chose tha moment do go mad and you'd find you have your period then as well! Hope you have a good appointment and get some good plans.